Navigating housing system complexity – Part II: Quantitative analysis of the Housing System Abstraction Hierarchy (HSAH)

Housing is a key component of urban systems, playing an essential role in shaping sustainable development and enhancing the resilience of cities. To achieve adequate housing, governments must adopt a systemic, integrated perspective on the housing system's structure, considering its complex interdependencies. Part I of this two-part study (the accompanying paper) introduced the Housing System Abstraction Hierarchy (HSAH), a conceptual framework for capturing the structural complexity of housing systems. Part II quantifies the HSAH, consisting of 176 nodes and 7822 interconnected links, using advanced network analysis metrics to identify the most influential components of the housing system and their functional dependencies. The results reveal that nodes with high Eigenvector Centrality, primarily within the economic, environmental, and technical domains, represent the most structurally influential parameters, whereas governance and social-related nodes with high Betweenness Centrality act as critical bridges facilitating cross-sectoral coordination within the housing system. Understanding these leverage points and network hubs provides policymakers with targeted entry paths for improving housing outcomes and driving system-wide transformation. Furthermore, the analysis traces cascading effects and systemic vulnerabilities, demonstrating how weaknesses in lower-level functional parameters can propagate and influence the system's higher-level objectives. Finally, the study highlights key insights from the policy paper on achieving adequate housing in Iran, developed based on the HSAH analysis, offering transferable insights for other developing and rapidly urbanizing contexts worldwide.